Technical Abstract:
Acid fuchsin and phloxine B are commonly used to stain nematodes in roots and egg masses on root surfaces, respectively. Both stains may be hazardous to the user and environment, and require costly disposal. We developed safer methods to replace both stains using McCormick Schilling red food color (RFC). Staining nematodes in root tissues: Roots were cleared with NaOCl, stained with a 12.5% solution of McCormick Schilling red food color (RFC), and destained briefly in acidified glycerin. Eggs, juveniles, and adult nematodes stained with RFC were equally as visible as those stained with acid fuchsin. Staining egg masses on root surfaces: Egg masses of Meloidogyne incognita on root surfaces were stained with a 20% solution of RFC for 15 minutes and rinsed in tap H2O. Egg masses stained with RFC appeared as bright red spheres on the root surfaces that were highly visible even without magnification. Replacement of acid fuchsin and phloxine B with RFC for staining nematodes in root tissue and egg masses on root surfaces, respectively, is safer for the user and for the environment, and also eliminates the costly waste disposal of used stain solutions.